Door lock



I J. MARSH DOOR LOCK July 30, 1940.

Filed Feb. 25, 1939 2 Sheets-Sheet 1 I ll In venior \w y llll'l y 00 l r5 g 1 4 p fi\ MU 7. My

A iiorneys DOOR LOCK Filed Feb. 25, 1939 I 2 Sheets-Shem 2 I i I II M l Q I l\\\\ I L 7 I .18 i2 23 2 32 Inventor JA MES MA R SH,

Patented July 30, 1940 UNITED STATES James Marsh, Rockford, Ill.,-assignor.of-one-ha1f to Ralph Ladd, Rockford, Ill.

.: Application'Februar'y'25, 1939,'Serial No. 258,531

soni 'sg (01192- 17 3) This invention relates todoor'locks, and has for the primary object the provision of a device of this character which combines in its construction a latch for a door and a key operated means 5 for locking the latch in door securing position so that the numberof parts will be materially reduced over a conventional construction of door lock to permit manufacture at a low cost with less liability of becoming inoperative or broken 10 and which includes a safety means to prevent the latch from being operated when a key is employed capable of unlocking the lock so that no possibility of the door being opened by an unauthorized person with the key from the outside of 15 the door will be had when the safety means is in use.

With these and other objects in view, the invention consists in certain novel features of construction, combination and arrangement of parts 20 to be hereinafter .more fully described and -,claimed.

For a complete understanding of my invention, reference is to be had to the following description and accompanying drawings, in which 25 Figure 1 is a side elevation illustrating a door lock constructed in accordance with my invention.

Figure 2 is an edge View illustrating the device.

Figure 3 is a side elevation with the cover plate 30 of the lock casing removed.

Figure 4 is a sectional view taken on the line 4-4 of Figure 3.

Figure 5 is a sectional view taken on the line 55 of Figure 3.

Figure 6 is a perspective view illustrating the latch bolt locking means.

Referring in detail to the drawings, the numeral 5 indicates a lock casing having a conventional face plate 6 provided with openings 1 to 4 receivescrews or like fasteners for securing the lock casing in a recess of a door. The lock casing has removable cover walls 8 in which are located aligned keyholes 9 and arcuately curved slots ill to slidably receive a knob shaft II to which knobs 4 l2 are secured. The face plate has a latch bolt opening l3 therein to slidably receive a. latch bolt The latch bolt has the conventional beveled end l5 to engage with a keeper (not shown) and is 50 further provided with a slot I 6 in which extends a lug I! carried by one of the cover plates. A coil spring I8 is arranged in the slot 16 between the lug I I and one end wall of the slot for the purpose of urging the latch bolt into keeper engaging position.

An arcuately c'urved'a'r-m I 9 is journaled on the knob shaft H and has its free end pivotally con nected to 'thelatch bolt, as shown at 20'. A fulcrum lug 2] is formed on one of the cover plates and has a pointed'end on which the arcuately 5 curved arm l9 may fulcrum. A downward sliding movement of the knob shaft ll brings about retraction of the latch bolt against the action of the spring l8. On freeing the knob shaft H the spring l8 returns the latch bolt into keeper engaging position.

Spaced guide lugs 22 are formed on one of the cover plates of the casing and slidably receive therebetween a locking bolt or member 23 having a cutaway portion to present converging key-engaging faces 24 terminating in a recess 25. The converging faces 24 and the recess 25 are arranged adjacent the key openings 9 so that when a key 26 is inserted in the key openings the bit 21 thereof may engage with the converging faces 24 and the recess for imparting a sliding movement to the locking bolt or member 23.

A spring-pressed tumbler 28 is pivoted in the lock casing directly under the locking bolt or member 23 and carries a pin 29 engageable with 25 shoulders 30 and 3| formed on the locking bolt or member 23. A leaf-type spring 32 bears against the tumbler for urging the same in a direction to bring the pin 29 thereof in engagement with the locking bolt or member. A portion of the tum- 90 bler underlies the recess 25 of the locking bolt or member so as to be engaged by the bit of the key when inserted in the lock casing.

To bring about locking of the latch bolt into keeper engaging position, the key, is inserted. in 35 the keyhole of the look casing with the bit 21 in engagement with the tumbler and one of the converging faces 24 of the locking bolt or member so that when the key is turned or rotated in one direction pivotal movement is imparted to the tumbler, moving the pin away from the shoulder 3| of the locking bolt and by the bit riding on one of the inclined faces the locking bolt is caused to slide between the guide lugs to occupy a position directly behind the latch bolt so that the latter cannot be retracted. When the locking bolt assumes the latter-named position the pin 29 engages with the shoulders 3l retaining the locking bolt in the position to prevent retraction of the latch bolt, consequently requiring the use of a key and the rotation thereof in a reverse direction to restore the locking bolt or member to its initial position as shown in Figure 3 or out of the path of movement of the latch bolt so that the V latter may be retracted by a downward movement of the knob shaft.

One of the cover plates of the casing is provided with an opening 34 in which a pin 35 may be inserted. When the pin is inserted in the opening 34 it engages the inner end of the latch bolt and consequently prevents the latch bolt from being retracted even though the locking bolt 23 has been returned to its initial position, as shown in Figure 3, through the use of the key. Consequently, the use of the pin 35 in the opening 34 provides a safety means for securing the latch bolt in latching position from the inside of the door so that even if the locking bolt 23 is moved into the position as shown in Figure 3 through the use of a key from the outside of the door, still the door cannot be released due to the fact that the latch bolt is retained in latching position by the pin.

It is believed that the foregoing description, when taken in connection with the drawings will fully set forth the construction and advantages of my invention to those skilled in the art to which such a device relates, so that further detailed description will not be required.

What I claim is:

l. A look comprising a casing having a latch opening, a latch bolt slidable in said opening and provided with a slot, a lug in said casing and extending into the slot for slidably supporting the latch bolt, a spring engaging said lug and latch bolt for urging the latter into latching position, a knob shaft slidably mounted in the casing for upward and downward movements relative to said latch bolt, an arcuately curved arm fixed at one end on said shaft and having its opposite end pivoted to said latch bolt, and a fixed abutment in said casing at one side of said arm coacting with the latter under downward sliding of said shaft to cause said arm to fulcrum thereon and thereby retract said bolt.

2. A lock comprising a casing having a latch opening, a latch bolt slidable in said opening and provided with a slot, a lug in said casing and extending into the slot for slidably supporting the latch bolt, a spring engaging said lug and latch bolt for urging the latter into latching position, a knob shaft slidably mounted in the casing for upward and downward movement relative to said latch bolt, an arcuately curved arm fixed at one end on said shaft and having its opposite end pivoted to said latch bolt, and a fixed abutment in said casing at one side of said arm coacting with the latter under downward sliding of said shaft to cause said arm to fulcrum thereon with a sliding action and thereby retract said bolt.

J AlVIES MARSH. 

